The present invention relates to open celled foams and, in particular, to open celled polyimide-polyamide foams, having densities no greater than 0.5 pounds per cubic foot, wherein the ratio of imide groups to amide groups is greater than 1 to 1 (hereinafter "polyimide-polyamide foams") and a process for forming such low density foams.
While foams and other insulations having densities of 0.5 pounds per cubic foot (pcf) or greater are quite suitable in many applications, for certain applications, such as aircraft, lower density insulations are preferred. With regard to applications for low density insulations, such as aircraft, spacecraft and the like, there is a continuing need to reduce the overall weight of the craft or vehicle by reducing the weight of the insulation materials used in the craft or vehicle without an appreciable loss in thermal and acoustical insulating performance. The low density polyimide foams of the present invention and the method of making such foams provide a solution to the need for low density, high performance insulating materials in many applications including but not limited to, aircraft, spacecraft and similar applications.